Requirements for SQL 2012 Always On and Avalability Groups feature

I am trying to test SQL Server Always On Feature, Availability Groups in SQL 2012. I have one basic question in terms of how it is different from 2008 Install. I have highlighted my questions in Italics, please try to answer each my questions

In SQL 2008 install on a 2 cluster, I perform the Install on the first node and then perform 'Add Node' on the second node to complete the Install. If it were 2012, to make use of this feature, do I have to install 2 separate Instances of SQL on the 2 nodes?

In point 8, it says the drive location has to be exactly the same across all nodes. In 2008, a drive letter is handled by only one node at a given time. How can I have exactly same location across all the nodes? Does it mean I have to install 2 separate Installs (and not 'Add Node' Install)?

How many IP addresses do I need to perform the Insall? In 2008 I needed just one Virtual IP for the SQL Virtual Name and performed the Install. In 2012 install with AG groups, how many IP's do I need?